A comprehensive set of accurate atomic data is required for analyses of
astrophysical and solar spectra. CHIANTI provides a database of atomic
energy levels, wavelengths, radiative data and electron excitation data
for ions which are abundant in cosmic plasmas. The most recent electron
excitation data have been assessed and stored following the method of
Burgess & Tully (1992). The current version is essentially complete
for specifying the emission spectrum at wavelengths greater than 50
Å. A list of observed lines in the spectral region between 50 and
1100 Åhas been compiled and compared with the lines predicted by
the CHIANTI database. The CHIANTI database reproduces the vast
majority of lines observed at these wavelengths. CHIANTI includes IDL
(Interactive Data Language) routines to calculate optically thin
synthetic spectra for equilibrium conditions. IDL routines to
calculate theoretical line intensities required for electron density or
temperature diagnostics and emission measure studies are also
included. The CHIANTI atomic database and supporting IDL routines are
available by anonymous FTP.